whittingham



(No Model.) 2 Sheets-Sheet 1.

G. H. WHITT INGHAM. AUTOMATIC ELECTRIC SWITCH.

No. 415,487 Patented Nov. 19, 1889.

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2 Sheets-Sheet 2.

(No Model.)

v G. H. WHITTINGHAM.

AUTOMATIC ELECTRIC SWITCH.

Patented Nov. 19,1889.

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UNITED STATES. PATENT OFFICE.

GEORGE H. \VHITTINGHAM, OF BALTIMORE, MARYLAND, ASSIGNOR TO THE AUTOMATIC ELECTRIC SIVITCH COMPANY, OF SAME PLACE.

AUTOMATIC ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 415,487, dated November 19, 1889. Application filed Iebruary 21, 1889. Serial No. 300,718. (No model.)

To all whom; it may concern.- branch of main-linecurrent. Fig. 3 is a dia- Be it known that I, GEORGE H. WVHITTING- gram showing helix operated by independ- HAM, acitizen of theUnited States, and a resient circuit. Fig. at is a diagram showing dent of the city of Baltimore and State of modified form of resistance device operated 5 Maryland, have invented certain new and by main-line current.

I useful Improvements in Automatic Switches Referring to Fig. 1, 1 is the main line carfor Electric Motors, of which the following is rying current from generator; 2, switch; 3,

;a full and complete specification, reference solenoid formed of main-line wire; 4, solenbeing had to the accompanying drawings. oid-core; 5, resistance-bar pivoted at 6 and 10 This invention has relation to an electric engaging contact-plate 7 in field-magnet line switch and mechanism operating in connec- 8 and resistance-coil 9 in armature-line 10. tion therewithfor' starting and stopping an The resistance-bar 5 is securely attached to electric motor or other electrical device, the the stud 6, and on said stud is keyed the object of the invention being to deliver the ratchet-wheel 11. J ournaled freely 011 the I 5 current to the motor or other device gradually stud 6 is the gear 12, said gear meshing with instead'of suddenly turning on the full force pinion 13, keyed to a stud let set in plate 15. of the line-current, and to do this automati- On the same stud let is keyed the gear 16, cally,'although the switch may have been which meshes Wllh fi/ pinion 17, keyed to a turned on full, as is usually done by ignorant stud 18, also set into plate 15. On the top of 20 persons also, to automatically replace a large this stud 18 is secured a fan 19, the revolution resistance in the circuit, whether to armaof which governs the motion of the resistanceture or field, Whenever the current is shutbar 5 when reducing the resistance. On the down or broken. A full current suddenly top of gear 12 is pivoted a pawl 20, which enturned onto the armature or field would be gages the ratchet-wheel 11, secured to the re- 2 5 likely to do great damage by burning out the sistance-bar 5, and connects said bar with the insulation at some point. The gist of my intrain 12 13 16 17 and fan 19, by which its movention, however, lies in the three following tion in one direction is governed. The core features: First, automatically reducing the 4 is secured to the resistance-bar in any suitresistance of a circuit afterthe current has able manner, and serves to move the resist- 0 been turned on by'a switch, and doing this ance-bar in one direction when a current is under the control of a governor, which 0011- passed through-the helix 3. To the opposite trols and regulates the motion of the autoside of the resistancebar is secured a rematic resistance-reducing d'vices to any detractile spring 21, the other end of which is sired speed; second, automatically replacing attached to a stud or screw 22 set in the frame 3 5 the resistance in the circuit when the current of the device. The end of the resistance-bar is shut down or switched off, as would occur 5 is provided with two contact-fingers, one by a stoppage of the generating-dynamo or 23engaging the plate 7 and sending current operation of the switch; and, third, leaving to the field-magnets of the motor, and the the apparatus when the current has been other-Qt-making contact with the resist- 4o shut down or switched off in such position ance-coils 9, and sending current through 0 that it will operate automatically to start the said coils to the armature of the motor. The motor-and repeat the first-mentioned operresistance-coils 9 are of any usual form and ation-that is to say, out out the resistance consist of plates of metal insulated from one automatically and gradually without being another, except where they are connected by 45 touched. coils of German-silver or other wire. 5

In the drawings, Figure 1 is a diagram of The operation of this device is as follows: my switch, showing helix for moving resisthen a current is turned on the line by opance-bar operated by main-line current which eration of the switch 2, it will flow through passes to both armature and field. Fig. 2 is a the solenoid-coil 3 down the resistance-bar 5,

5o diagram showing helix operated by fielddivide at the end, and part go through finger Ioo 23, plate 7, and wire 8 to field of motor, the other part through finger 24, resistancecoils 9, and line 10 to armature. The passage of the current through the resistance-coils 9 will so reduce it as to prevent its injuring the armature and cause the armature to start slowly. As soon as the current begins to flow through the solenoid 3 it will attract its armature and begin to pull the resistance-bar toward the solenoid and thus cut out the resistance, notwithstanding the retractile influence of the spring 21,which acts in an opposite direction, the solenoid being stronger than the spring; but in order to safely start the motor the current must be put on gradually until the speed of the armature is great enough to generate sufficient counter electro-motive force to prevent the full current doing any harm. This gradual motion of the resistance-bar is produced by the train 12 13 16 17 and fan 19, which are connected to the resistance-bar by the pawl 20 and ratchet-wheel 11. If now the generator of current be shut down wholly or partially, or the switch turned so as to cut oft all of the current, the solenoid will at once cease to act and the spring 21 will draw the resistance-bar back to its primary position, as shown in Fig. 1. This action should be a quick one, because if the current is suddenly cut otf and then turned on again, unless the resistance be reintroduced into the circuit, all the bad effects of a full current suddenly turned on the armature will result, and this is one of the especial features of my invention and one that is not found in any device heretofore invented. It will be noticed that this action is purely automatic and instantaneous.

Referring now to Fig. 2, the structure there shown is identical with that of Fig. 1, except that the wiring is different. The solenoid in 7 this case is formed of the field-magnet wire,

and the resistance-bar has but one finger.

Referring to Fig. 3, the structure is here again identical, but wiring is different. In this case an independent circuit is employed to operate the solenoid, which in its turn is switched by the operation of a solenoid placed in the main-line circuit.

Referring to Fig. 4, a different form of device for cutting resistance'in and out of the circuit is shown. This device consists of a plate 25, through which the line passes, and a conducting-bridge 26, one end of which rests upon the plate 25 and the other end upon one of the plates 27 of the resistance coils. To the bridge is secured a rod 28, extending on either side of it. 011 one end of this rod is attached a plunger 29, which fits into a dash-pot 30 and controls the motion of the bridge in onedirection, a valve in plunger leaving bridge free to move in opposite directions. The other end of the rod 28 is secured to the helix-core 4, by which the bridge is drawn over the resistance-plates and the resistance thus removed from the circuit. The spring 31, secured to the stud 32 at one end, bears with its other end upon the core 4, and serves,.when the current is withdrawn, to push the bridge 26 back to its primary position and thus reintroduce the resistance into the circuit, where it will be ready to protect the armature when the current is again put on the line.

I have illustrated these several forms of structure, through which my invention may be applied for the purpose of showing that my invention and claim is not and should not be confined to any one of these forms, but includes them all or any modification of them by which my invention may be utilized.

lVhat I claim as new is- In an automatic switch, the combination of a main line which is (lhltled into two branches, said branches reuniting again, an electric motor the field of which is included in one branch and the armature in the other, resistance-coils and a resistance-bar co-operat-ing therewith to cut portions of said resistance into or out of the circuit included in the armature branch of the main line, a governor connected to and controlling the motion of the resistance-bar in the direction in which it reduces the resistance in the armature-circuit, but allowing it to move freelyin the opposite direction, and an electrical device controlled by the main-line current for moving the resistance-bar in the direction in which it will reduce the resistance in the armaturecircuit, and a spring or other equivalent device for moving the bar in the opposite direc-- tion, substantially as described.

In witness whereof I have hereunto set my hand this 14th day of February, 1889.

GEORGE ll. "III'PJINGIIAU. Attest:

FELIX R. SULLIVAN, GEO. E. SAVILLE. 

